摘要:Shading of solar panels drastically reduces the solar collector’s efficiency “η” by reducing cell power “PMP”, and altering the short circuit-current “ISC”, the open-circuit voltage “VOC”, and the fill factor “FF”. Therefore, the orientation and tilt angle of solar collectors play an important role in minimizing shading and consequently in increasing solar collector’s efficiency. A mathematical methodology including Cooper’s equation and Visual Basic Application (VBA) programming in Microsoft Excel was utilized to determine optimum tilt angles for solar collectors installed in Kuala Lumpur, Malaysia. The mathematical approach was devised to determine the optimal arrangement in flat fields, field with steps and inclined field. The result indicates that the worst shading effects happens during December and an optimum flat distance between solar collector rows for a flat field is 2.66 m for a 2 m high collector meanwhile for field with steps and inclined field, the arrangement of solar panel is depended on slope or tilt angle ß which is presented in relevant graphs. The result is useful for the contractors, developers and consulting firms who are running projects in Kuala Lumpur, Malaysia.